This invention is generally relative to a Multiple Input Multiple Output Multiple-Input Multiple-Output wireless sensor networks communication.
Conventional deployments of sensor networks communication often scatter multiple sensors over a limited geographic region in order to collect data of interest. The collected data is then analyzed to expeditiously achieve or facilitate a given mission objective. It does not matter whether the collected data is continued surveillance, reconnaissance, target identification, registration and disposition, or anything else along those lines. In the sensor networks communication, each sensor device is expected to reliably and securely transmit its data to a communication receiver for further analysis, pattern recognition, coordination, and processing during various time intervals. Usually, each sensor has a single antenna while the communication receiver is equipped with an antenna array, which has many elements. Different sensors in the sensor networks communication may be responsible for different levels of throughput and fidelity depending on a particular task. In addition, some sensors in the sensor networks communication may have to provide several transmissions within a short-time interval while as other sensors may only transmit at irregular intervals or even not at all. Thus, resource allocations of the sensor networks communication need be determined and continually reassessed so that accommodations of such versatility can be achieved in performance.
The further sensor networks communications are envisioned to contain a large number of sensor nodes, each capable of some limited computation, communication and sensing capabilities, operating in an unattended mode with limited energy. They are also characterized by severe energy constraints because the sensor nodes will often operate with finite battery resources and limited recharging. Generally speaking, they have the following properties: (1) A sensor network communication is composed of a large number of sensor nodes that are densely deployed either inside the phenomenon or very close to it; (2) Sensor nodes in the sensor networks communications are prone to failures; (3) A topology of the sensor networks communications changes very frequently; (4) Sensor nodes in the sensor networks communications mainly use a broadcast communication paradigm; (5) Sensor nodes in the sensor networks communications are limited in power, computational capacities, adaptive communication signal processing, transmission, and memory; and (6) in addition, in some cases, sensor nodes of the sensor networks communications may not have global identification because the sensor networks communications use a larger amount of overhead and large number of sensors.
A sensor networks communication has numerous applications. One of the applications is used to monitor and control safely critical military and governmental environments such as domestic infrastructure systems. In this case, the application may include battlefield detection and protection systems for biological, chemical and/or radiological weapons, aiding areas hit by disasters. Another of the applications is used for homeland security at airports, bridges, public building, and major subway train systems. A third-one of the applications is used for tracking. For example, a ship in the ocean emits sounds that may be detected and characterized by several underwater senor networks. As the ship moves, the bearing measurements slowly change. A fourth-one of the applications is in smart spaces that may include semiconductor and/or manufactory facilities, smart building, cities, and even sensitive laboratories. A fifth-one of the applications is used to monitor ground temperature such as a forest to detect fast moving forest fires. A sixth-one of the applications is in entertainment environments including amusement parks and/or museums. In addition, other applications are in health case systems such as higher-age health monitor and/or patient health and movement status at home environment. As can be seen, the sensor networks communication has tremendous application value not only in military battlefield but also in commercialization.
Recent advances in integrated circuits technology have enabled mass production of tiny, cost-effective, and energy-efficient seamless sensor devices with processing capabilities. The seamless sensor devices are usually equipped with a sensor module in which detects via electrical/electromagnetic fields, acoustics, optical, movement, chemicals, biological agents, radiation, environmental factors such as humidity, temperature, and so on. Characteristics of the seamless sensor devices to be considered are size, battery consumption, energy level, lifetime, movement whether a sensor is mobile or must remain stationary, position that the sensor may be embedded or may be independent of its surroundings, redundancy for checking integrity, and failure modes. The malfunctions may indicate that the sensor has failed, is degrading slowly, or possesses a bad behavior such as going up and down randomly.
Advanced sensor networks communication is expected to utilize a larger of size sensor nodes, such as 1000, or even more individual sensor nodes in potentially hostile and militarily sensitive environments. Every sensor node of the sensor networks communication is likely to support data collection and transmission in an efficient, robust, reliable and secure communication fashion. The sensor network communication will encounter to have multipath propagation because sensor network elements are not likely to be guaranteed a line-of-sight transmission path to a communication receiver, which is not promised to remain at a fixed position for any period of time. The multipath propagation arises from scattering, reflection, refraction or diffraction of the radiated energy off objects in the environment. Thus, received signals from sensor nodes are much weaker than transmitted signals due to mean propagation loss. In addition to a mean path loss, the received signals exhibit fluctuations in a signal level that is referred to fading. Moreover, the sensor networks communication may also have interference, such as co-channel interference (CCI), adjacent-channel interference (ACI), and intersymbol interference (ISI). On the other hand, the sensor networks communication may likely have jam resistant in a hostile and militarily sensitive or a battlefield. Therefore, to effectively operate under the abovementioned constraints, we invent using adaptive novel communication signal processing approaches of space-time processing along with MIMO-based multi-sensor code division multiple access (CDMA) architecture for the sensor networks communication.
The present invention of the MIMO-based wireless sensor networks communication is not only responsible for frequency selection, carrier frequency generation, interleaver, error coding, channel estimate, signal detection, modulation, and source data encryption as well as strategies that overcome signal multipath propagation effects, but also responsible for architecture schemes including tiny, low-power, low-cost communication transceiver, sensing, analog-to-digital (A/D) and digital-to-analog (D/A) converters, and computing processing units and low power-efficient methods. Thus, there is a continuing need of the MIMO-based wireless sensor networks communication.